1. Technical Field
The present invention relates to geometric correction.
2. Background Art
A technique in which an input image is transformed into an arbitrary shape to obtain an output image is known. JP-A-2011-188051 discloses that, in a projector which carries out, on each block video data, correction processing to correct a distortion of a video projected on a projection surface, a block video necessary for pixel interpolation is predicted and stored in a block video storage unit, thereby reducing the time taken to read out and store a necessary block video anew at the time of carrying out pixel interpolation and thus achieving an increase in the speed of keystone correction processing.
In the technique disclosed in JP-A-2011-188051, pixel values of a video before correction are scanned obliquely to the direction of lines in order to specify pixel values of the video after correction, pixel by pixel in the direction of lines. Therefore, the technique disclosed in PTL 1 has a problem that a frame buffer for temporarily storing the video before correction is essential. There is also a problem that the access efficiency of the frame buffer drops due to the oblique scanning of the video before correction.